Air turns on and off?

Hows it going everybody, I was just hopping back in my truck from grabbing a coffee, start it up and the air is on with none of the air controls on. I drove it home and parked it, shut it off and the air was still on. So I go out to leave today and the battery's dead. Anybody have an idea why this is doing this? short in the fusebox? Any help would be greatly appreciated! Thanks!

could be the computer control box for the interior fan. the 03 i used to have did that to me once. $110 for the part and put it in and I was on my way, it sounds like yours is doing the exact same thing mine did.